Currently in the U.S., partially hydrogenated fats are employed in the production of many chemically leavened and yeast-raised bakery products (e.g., cakes, crackers, cookies). The partial hydrogenation of domestic oils originating from soybean, cottonseed, corn, sunflower, and/or canola allow the chemical reduction of the unsaturated fatty acids to saturated fatty acids which provide greater oxidative stability.
Hydrogenation is a physical modification of these liquid oils, imparting thereto a solid fat content and an increased melting point, as saturated fatty acids are solid at room temperature whereas unsaturated fatty acids are liquid at room temperature As a result, the oils which are naturally liquid can be transformed into a semi-solid fat with a particular melting profile. To provide maximum eating pleasure with this form of the fats, the hydrogenation process of these fats is highly controlled and allowed to proceed only partially, that is, to allow only some of the unsaturated fatty acids and/or bonds thereof to be reduced to the saturated form. These types of fats and fatty acids are called "partially hydrogenated fats" or "partially hydrogenated oils" or "partially hydrogenated fatty acids".
In addition to the reduction of the unsaturated fatty acids to the saturated form, in partial hydrogenation, a side reaction occurs in which the natural form of the unsaturated bond (referred to as a cis isomer) will twist in the plane, to form what is now referred to as a trans isomer of the bond of the of the unsaturated fatty acid.
Generally, cis isomers are those naturally occurring in food fats and oils. Although very small amounts of trans isomers occur in fats from ruminants or can result from the deodorization step in refining of vegetable fats and oils, most trans isomers result from the partial hydrogenation of fats and oils. Also, it is possible for the unsaturated bond to move laterally along the fatty acid chain and this is referred to as a positional isomer. These isomers are formed at the high temperatures (e.g., 180.degree.-240.degree. C.) common during the hydrogenation reaction and when the Nickel catalyst typically employed during the hydrogenation reaction unsuccessfully introduces a hydrogen atom to both sides of the unsaturated bond. These isomers are rather stable and will then remain unless the hydrogenation reaction is continued until there is a complete reduction of the unsaturated fatty acids. Therefore, partially hydrogenated fat will always contain some proportion of these positional and geometrical isomers; and, as discussed herein, those isomers can present problems.
For instance, typically, shortenings employed in bakery products may contain 15-25% trans isomers. The use of these isomers has become more scrutinized by nutritional science in the last several years. There have been clinical studies reporting observed negative health effects correlated to the presence of trans fatty acids formed during the partial hydrogenation of oils, e.g., a positive correlation with coronary heart diseases an increase in the ratio of plasma low density lipoproteins (LDL) to high density lipoproteins (HDL) and thus a possible increase in the risk of coronary heart disease (see, e.g., Elias, B. A., Food Ingredients Europe: Conference proceedings, London, October 1994 (Publisher: Process Press Europe, Maarssen); Willet, W. C. et al., Lancet 341 (8845); 581-585 (1993); Khosla, P. et al., J. Am. Col. of Nutrition, August 1996, 15(4):325-339 (American College of Nutrition, NY, N.Y.)).
Thus, a problem in the art is the use of partially hydrogenated fats and oils in foodstuff; and, a related problem is the need for a suitable replacement for partially hydrogenated fats and oils in foodstuff.
Fats or oils which contain naturally a sufficient amount of saturated fatty acids to form solids include palm oil, palm kernel oil, coconut oil, lard, and tallow.
However, in the U.S. the use of tropical fats or oils is basically limited to a few non-dairy and confectionery applications due to concerns relating to their naturally high content of short chain saturated fatty acids. Also the application of animal fats is restricted due to such issues religious dietary restrictions, e.g. rabinical law for kosher certification.
Thus, the problems presented by partially hydrogenated fats or oils cannot be addressed by merely employing naturally saturated fats or oils; and, the use of naturally saturated fats and oils present problems. It would be desirable to be able to employ naturally saturated fats or oils such as tropical fats or oils in more foodstuff, especially in more foodstuff in the U.S. than is currently typical, without triggering the bases for the concerns relating to their content of short chain saturated fatty acids.
Another possible replacement for partially hydrogenated fats or oils is interesterified fats based on liquid oils and fully hydrogenated fats. These interesterified fats are from a process wherein the fatty acids on the triglycerides of two fats are randomized, resulting in a triglyceride composition that can provide a suitable melting profile.
This option presents problems insofar as the food manufacturor or processor would be required to include the fully hydrogenated fat on the product label, and the ultimate consumer may likely associate trans isomers with the full or complete hydrogenation process, such that the food product would likely not be commercially successful.
Polyunsaturated fatty acids are considered a highly essential component of a healthy diet according to the U.S. Food and Nutritional Board's Recommended Dietary Allowances (tenth ed. 1989) (e.g., amound of dietary linoleic acid for humans should be a minimum of 2% of dietary calories and preferably 3%; and, the requirement for linolenic acid has been estimated to be 0.54% of calories)
While it would be desirable to replace partially hydrogenated fats simply with natural vegetable oils since natural vegetable oils have a relatively high ratio of polyunsaturated to saturated fatty acids, attempts to do this so far have also proven to be quite unsatisfactory in regard to either the processing or organoleptic (e.g., taste, texture, eating) aspects of the food product. For example, there may be insufficient oil retainment in the dough or batter resulting in separation of oil. Or, oils may depart from the food product too quickly in the mouth, imparting an off-taste and off-feel to the product as it is being consumed.
Another related problem in the preparation of food products is "bloom"; a phenomenon wherein certain fats or oils permeate to the surface of a food product, such as a cookie, and leave a scoring on the surface of the food product. This "bloom" renders the food product not visually appealing and ergo not consumable. It would be desirable to provide a shortening system which does not suffer from "bloom."
In the production of food surfactants or emulsifiers, a triglyceride is reacted with glycerol and to form a reaction product containing the desired product, the monoglycerides. Thus, the reaction product is typically subjected to a treatment to isolate a monoglycerides product from a diglycerides and triglycerides product; the diglycerides and triglycerides product is considered a by-product of the reaction of a triglyceride with a glycerol to obtain monoglycerides for surfactants or emulsifiers. The diglycerides and triglycerides product is sometimes discarded, or recycled back to a reactor wherein the reacting with glycerol is occurring so as to enhance the production of monoglycerides (see, e.g., Lauridsen, "Food Surfactants, Their Structure And Polymorphism Technical Paper TP 2-1e Danisco Ingredients, Braband Denmark, and references cited therein).
It would be desirable to provide alternative uses for this by product from emulsifier or surfactant preparation
Systems functioning as or containing fats or oils have been proposed (see, e.g., CN 1078353, U.S. Pat. Nos. 5,458,910, 5,612,080, 5,254,356, 5,061,506, 5,215,779, 5,064,670, 5,407,695, 4,865,866, 4,596,714, 4,137,338, 4,226,894, 4,234,606, 4,335,157, 3,914,452, 3,623,888, DD 291240A). However, these systems have not sufficiently addressed the problems in the art; and, these systems have not been reported to provide the synergistic, and surprisingly superior properties, including improvement in organoleptic properties of foodstuff, of the present invention.